Prevention of murine cerebral malaria by low-dose cyclosporin A.

The effects of cyclosporin A (CsA) were investigated in an experimental model of cerebral malaria. In this model, Plasmodium berghei ANKA-infected CBA/Ca mice develop a clinically and histologically characterized neurological syndrome which is considered to be the result of immunopathological reactions mediated by L3T4+ T cells. It was shown that CsA displayed a strong protective effect on neurological complications when given at a dose 1 mg/kg/day for 5 consecutive days (Days 4-8), which had no effect on the parasite. Paradoxically, this protection against neurological complications was not seen when parasiticidal doses were used during this limited 5-day period. A similar protective effect was observed with two CsA derivatives, C5-34 and H7-94. The mechanisms by which CsA and the two derivatives could prevent murine cerebral malaria are unknown but can be related to exquisite effects on some lymphocyte functions. In view of these results, it might be conceivable to investigate the benefits of using low doses of CsA in man, in conjunction with the classical antiparasite therapy, for the management of cerebral malaria.